Support for checking space usage in compiled sketches via command line

Author: ianfixes

Diff for: CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Support for `dtostrf()`
 - Added a CI workflow to lint the code base
 - Added a CI workflow to check for spelling errors
+- Extraction of byes usage in a compiled sketch is now calculated in a method: `ArduinoBackend.last_bytes_usage`
 
 ### Changed
 - We now compile a shared library to be used for each test.

Diff for: exe/arduino_ci.rb

@@ -24,7 +24,7 @@ def self.parse(options)
       ci_config: {
         "unittest" => unit_config
       },
-      min_free_space: 0,
+      min_free_space: nil,
     }
 
     opt_parser = OptionParser.new do |opts|
@@ -50,7 +50,7 @@ def self.parse(options)
         unit_config["testfiles"]["reject"] << p
       end
 
-      opts.on("--min-free-space=VALUE", "Minimum free SRAM memory for stack/heap") do |p|
+      opts.on("--min-free-space=VALUE", "Minimum free SRAM memory for stack/heap, in bytes") do |p|
         output_options[:min_free_space] = p.to_i
       end
 
@@ -502,23 +502,20 @@ def perform_example_compilation_tests(cpp_library, config)
       board = ovr_config.platform_info[p][:board]
       attempt("Compiling #{example_name} for #{board}") do
         ret = @backend.compile_sketch(example_path, board)
-        puts
-        if ret
-          output = @backend.last_msg
-          puts output
-          i = output.index("leaving")
-          free_space = output[i + 8..-1].to_i
-          min_free_space = @cli_options[:min_free_space]
-          if free_space < min_free_space
-            puts "Free space of #{free_space} is less than minimum of #{min_free_space}"
-            ret = false
-          end
-        else
+        unless ret
           puts "Last command: #{@backend.last_msg}"
           puts @backend.last_err
         end
         ret
       end
+
+      next if @cli_options[:min_free_space].nil?
+
+      usage = @backend.last_bytes_usage
+      min_free_space = @cli_options[:min_free_space]
+      attempt("Checking that free space of #{usage[:free]} is less than desired minimum #{min_free_space}") do
+        min_free_space <= usage[:free]
+      end
     end
   end
 end

Diff for: lib/arduino_ci/arduino_backend.rb

@@ -235,5 +235,21 @@ def install_local_library(path)
       Host.symlink(src_path, destination_path)
       cpp_library
     end
+
+    # extract the "Free space remaining" amount from the last run
+    # @return [Hash] the usage, as a hash with keys :free, :max, and :globals
+    def last_bytes_usage
+      # Free-spacing syntax for regexes is not working today, not sure why. Make a string and convert to regex.
+      re_str = [
+        'Global variables use (?<globals>\d+) bytes',
+        '\(\d+%\) of dynamic memory,',
+        'leaving (?<free>\d+) bytes for local variables.',
+        'Maximum is (?<max>\d+) bytes.'
+      ].join(" ")
+      mem_info = Regexp.new(re_str).match(@last_msg)
+      return {} if mem_info.nil?
+
+      Hash[mem_info.names.map(&:to_sym).zip(mem_info.captures.map(&:to_i))]
+    end
   end
 end

Diff for: spec/arduino_backend_spec.rb

@@ -103,5 +103,13 @@ def get_sketch(dir, file)
     it "Passes a simple INO sketch at #{sketch_path_ino}" do
       expect(backend.compile_sketch(sketch_path_ino, "arduino:avr:uno")).to be true
     end
+
+    it "Detects the bytes usage after compiling a sketch" do
+      expect(backend.compile_sketch(sketch_path_ino, "arduino:avr:uno")).to be true
+      the_bytes = backend.last_bytes_usage
+      expect(the_bytes[:globals]).to eq 9
+      expect(the_bytes[:free]).to eq 2039
+      expect(the_bytes[:max]).to eq 2048
+    end
   end
 end